A battery rack having a plurality of battery modules loaded thereon includes a frame fabricated to have an appropriate hexahedron shape, a plurality of horizontal lathes dividing the frame into a plurality of levels and installing and fixing the battery modules therein, side, upper, lower and back panels respectively fixed to the sides, top, bottom and back of the frame, and a door or a front panel coupled to the front portion of the frame.
The battery rack is coupled to a predetermined cooling device in order to appropriately maintain temperature of the battery modules installed inside the rack. For coupling the cooling device, slits are formed in the upper and lower panels of the battery rack to allow a passage of a refrigerant such as air. The upper and lower panels are respectively connected to a refrigerant introduction duct and a refrigerant releasing duct. In this configuration, if a refrigerant forcibly blows into the refrigerant introduction duct or forcibly discharges from the refrigerant releasing duct, a refrigerant flows from the top to the bottom in the battery rack, and the refrigerant flowing from the top to the bottom passes through channels (slits) formed in the battery modules fixed in the lathes. In this process, the heat generated from the battery modules is absorbed by the refrigerant and discharged to the outside.
FIG. 1 is a schematic view showing a conventional battery cooling system to which the refrigerant flow as described above is applied.
Referring to FIG. 1, the conventional battery cooling system has a structure in which a cooling channel is formed in a battery rack 1, where battery modules 2 stacked in vertical direction are loaded, to pass through the battery modules 2 in the direction from the top to the bottom thereof (see an arrow direction in FIG. 1).
In this case, a temperature variation appears between the battery modules 2 loaded in different levels and the cooling channel elongates to cause relatively large differential pressure therebetween. The relatively large differential pressure works as a factor increasing the temperature variation of the battery modules 2 loaded in different levels.
Generally, the lifespan of a battery significantly deteriorates if internal temperature of the battery exceeds a specific temperature. Therefore, the temperature variation between the battery modules 2 loaded in different levels of the battery rack 1 negatively affects the operation performance and the lifetime of the battery modules 2.
Accordingly, a battery cooling system for minimizing a temperature variation between the battery modules loaded in a battery rack is in great demand.
Meanwhile, since a conventional battery rack is commonly placed at the inside of a car or in power transmission facilities, people or users are not likely to see the same. However, since facilities such as an energy storage system, an electric vehicle charge device, or the like are more likely to be placed in a house or at a place having a large floating population, a battery cooling system having a fine appearance, albeit a cooling device loaded thereon, is also in demand.